Laminating resins having low organic emissions

ABSTRACT

A laminating resin is made from (1) an unsaturated polyester resin, (2) a diacrylate or dimethacrylate of alkoxylated bisphenol-A, and (3) vinyl toluene. The resin requires no styrene to achieve excellent laminating resin properties, and is significantly inhibited from emitting volatiles during use.

RELATED APPLICATIONS

This application is a continuation-in-part of our application Ser. No.024,022, filed Mar. 1, 1993, now abandoned, of the same title.

TECHNICAL FIELD

This invention relates to resin compositions which cure as they areshaped, laminated, brushed, sprayed or otherwise more or lessincrementally placed into the space where they are to form a product;such resins are broadly known as laminating resins, commonly have anunsaturated polyester resin base, are mixed with glass fiberreinforcement, and nearly always are employed in a solution of anorganic monomer such as styrene. The organic monomer is intended tocopolymerize with the resin but typically and notoriously may also tendto volatilize in significant amounts into the workplace environment. Thepresent invention is a composition and method which can be used inexisting equipment, procedures, and workplaces, but which will emit farless monomer than the typical laminating resin and method heretofore.

BACKGROUND OF THE INVENTION

Many attempts have been made to devise laminating resins having lowvolatile emissions and still meet the physical specifications and otherdesirable properties of the end products, while remaining relativelyeasy to use. In Lee U.S. Pat. No. 4,465,806, for example, a more or lessconventional unsaturated polyester resin is combined with, instead ofthe usual styrene, a reaction product of a polyepoxy compound andacrylic or methacrylic acid which may be the diacrylate of apolyglycidyl ether of bisphenol-A. These compounds are made from epoxycompounds, and the author of U.S. Pat. No. 4,465,806 requires that asignificant portion of the epoxy groups be unreacted for use in theirresin. Moreover, unlike the present invention, they form pendant OHgroups.

Ethoxylated, difunctional, bisphenol-A has been used in the past as aningredient in various types of resins, generally resins which include asignificant diisocyanate component, as in Ford, Jr. et al U.S. Pat. No.3,876,726.

European Patent Application 0 234 692 discloses a composition said to beuseful as a molding resin, having the virtue of a low residual monomerconcentration in the final product. The gist of the disclosure appearsto be that dimethacrylates such as ethoxylated bisphenol-Adimethacrylate can be used as components of otherwise more or lessconventional unsaturated polyester resins to reduce the amount ofresidual styrene monomer in contained molding processes such as cellmolding, compression molding, and sheet molding. See also Reid and RexU.S. Pat. No. 5,202,366, which includes a low-profile additive in asimilar composition.

The daunting problem of volatile emissions during spray-up or otherlaminating procedures has until now been unsolved. Applicants' dramaticresults detailed herein show that lamination can be used withsignificantly reduced emissions in the workplace.

SUMMARY OF THE INVENTION

Our new laminating resin comprises three components. The first is a baseresin comprising glycols and unsaturated dicarboxylic acids; optionallythe base resin may also contain a saturated dicarboxylic acid. Inpolymeric form, they are typically maleic and phthalic acid residues,with optional isophthalic residues, interspersed with glycol residues.These glycols are commonly ethylene glycol, diethylene glycol, propyleneglycol and dipropylene glycol, usually as mixtures, but many otherglycols can be utilized; dicyclopentadiene may be included as well, asis known in the art. The second component is a diacrylate ordimethacrylate of alkoxylated bisphenol-A of the formula ##STR1## wherem and n are independently numbers from 1 to about 10, and R¹ and R² areindependently, in each alkoxy group, hydrogen or CH₃. Hydroxyethyl orhydroxypropyl groups should comprise about 19-71% of the weight of thisingredient. These two ingredients may be present in weight ratios ofabout 2.0:1 to about 0.5:1. The composition also includes about 20-60%based on the total of the two above ingredients of a compound of theformula ##STR2## where one H connected to the ring is substituted byCH₃. The above-described composition may also include from 1% to about10% of N-vinyl pyrrolidone or 1% to about 20% cyclohexyl methacrylate orboth, and/or 1% to about 30% ethylene glycol dimethacrylate, all basedon overall composition. Since our objective is to design a compositionwhich works very well as a laminating resin without significant styreneemissions, the addition of styrene to the recipe defeats that purposeand is not recommended, but the composition will continue to be operableas an excellent laminating resin even though some styrene is included.The composition will also tolerate many other minor ingredients known tobe useful in the unsaturated polyester and laminating art. A volatilityof 20.0 g/m² or less, as measured by the test of Section 1162 of theRegulations of the South Coast (California) Air Quality District, wassignificantly achieved by applicants in the present invention. In fact,applicants' resins all measured under 10.0 g/m².

DETAILED DESCRIPTION OF THE INVENTION

While the problem at hand is to create a formulation which drasticallydiffers from commercial standard laminating resins in terms of volatileemissions during application, the market dictates that it must beaccomplished without significantly altering the widely used equipmentand techniques of application. Accordingly, the following criteria areto be kept in mind at all times:

1. Reduced emission of volatile organic compounds--regulations willbecome more stringent with time.

2. Less potential hazard to human health and theenvironment--regulations will also become more stringent with time.

3. Minimal increase in cost when commercialized, and reason to believecost will be reduced in the long run.

4. Compatibility between components of the resin system.

5. Reactivity that is similar to that of styrenated polyester resins.

6. Viscosity that is similar to that of styrenated polyester resins--100to 400 cps.

7. Physical properties similar to or better than those of styrenatedpolyester resin.

8. Ability to wet glass and bond to other components of an assembly.

Persons skilled in the art will realize that number 7, relating tophysical properties of the final product, can by itself include severalimportant specifications. Thus, the problem is not simply one of findinga monomer which is not as volatile or objectionable as styrene. Rather,many criteria have to be balanced, and, with thousands of chemicals toconsider, analysis of the combinations and their effects is extremelydifficult. One must decide on the important functions and properties,settle on a systematic but simple screening process, and try to developa short list of prospective formulations which have a good chance ofmeeting all the criteria within a practical time period.

The proliferation of input variables to attain these objectives may befurther appreciated by considering the more or less conventionalunsaturated polyester compositions which may be used as a base. They areprepared by polycondensation of polycarboxylic acid derivatives, one ofwhich must be an alpha, beta-ethylenically unsaturated polycarboxylicacid, and polyols. By polycarboxylic acid derivatives we mean to includepolycarboxylic acids, their esters of lower alcohols, their acidchlorides and their anhydrides.

The ratio of polycarboxylic acid to polyol is usually a 1:1 molar ratio.However, in most esterification processes, a slight excess of polyol isutilized to compensate for polyol losses during esterification. Also,although dicarboxylic acids and diols are most frequently utilized andthe 1:1 molar ratio is prevalent, the utilization of triols and the likerequires the ratio of acid to polyol to be stated more precisely as oneequivalent of acid per equivalent of polyol.

The unsaturated polyesters useful in this invention may be prepared froman acid mixture wherein the unsaturated polycarboxylic acid comprises aslittle as 20 mole percent of the total acids present, although it isgenerally preferred that the unsaturated polycarboxylic acid comprisesabout 30% or more of the total acid content.

Some of the unsaturated polycarboxylic acids useful in preparingunsaturated polyesters used in this invention include:

    ______________________________________    Maleic acid        Citraconic acid    Fumaric acid       Glutaconic acid    Itaconic acid      Chloromaleic acid    Mesaconic acid    ______________________________________

and the like, wherein the term "acid" is used to include thecorresponding anhydrides where such anhydrides exist.

Some of the saturated and aromatically unsaturated polycarboxylic acidsoptionally useful in preparing unsaturated polyesters used in thisinvention include:

    ______________________________________    Phthalic acid       Isophthalic acid    Tetrahydrophthalic acid                        Hexahydrophthalic acid    Endomethylene tetrahydrophthalic                        Glutaric acid    acid                Suberic acid    Tetrachlorophthalic acid                        Sebacic acid    Hexachloroendomethylene    tetrahydrophthalic acid    Succinic acid    Adipic acid    ______________________________________

and the like, wherein the term "acid" includes the correspondinganhydrides where such anhydrides exist.

Polyols useful in preparing polyesters for use in this invention arepolyfunctional alcohols of the type conventionally utilized in polyesterpreparation. Such polyols include:

    ______________________________________    Ethylene glycol      1,5 propanediol    Propylene glycol     Triethylene glycol    Butylene glycol      Glycerol    Diethylene glycol    1,4,6-hexanetriol    Trimethylolpropane   Trimethylolethane    Dipropylene glycol   Pentaerythritol    Neopentyl glycol    Alkoxylated 2,2-bis(4-hydroxyphenyl)    propane    ______________________________________

and the like. Although diols are generally preferred in the preparationof unsaturated polyesters, the more functional polyols, i.e. polyolshaving a functionality of three to five, are sometimes used.

In addition, dicyclopentadiene may be included and may be considered anormal part of the "base resin" as used herein.

During the development of the formulation, various monomers and monomersubstitutes were screened, using two different "base" resins--one havingdicyclopentadiene as a major ingredient and one withoutdicyclopentadiene. Following are results for the base resin withoutdicyclopentadiene:

A base resin composition (hereafter designated "Resin A") was preparedhaving the following ingredients:

    ______________________________________    Base Resin*           60 parts by weight    12% Cobalt (Promoter) 00.30    Potassium (Co-promoter)                          00.20    N,N-Dimethylacetoacetamide                          00.30    (Accelerator)    DDM-9 (Initiator)     01.50    Monomer (as indicated below)                          40    ______________________________________    *Base Resin Parts by lbs/100 lbs/60    (Polymer)   weight   lbs     lbs    Propylene Glycol                22.788    31.97  19.18    Diethylene Glycol                04.937    6.93    4.16    Phthalic Anhydride                32.734    45.92  27.55    Maleic Anhydride                10.820    15.18   9.11                71.279   100.00  60.00

The following "monomers" were utilized with Resin A:

    __________________________________________________________________________                            Exotherm                                  Gel Time                                       Interval    Monomer     Mod L.sup.1)                     Viscosity                            °F.                                  min:sec                                       min:sec    __________________________________________________________________________    Styrene     0.120                     low    335   4:30 4:39    Vinyl Toluene                0.120                     low    317   4:50 5:04    Diallyl phthalate                0.000                     high   119   19:27                                       27:43    Methacrylates    n-butyl     0.001                     low    186   40:58                                       5:28    n-hexyl     0.001                     incompatible    isodecyl    0.001                     incompatible    cyclohexyl  0.001                     high*  287   16:50                                       3:50    2-phenoxyethyl                0.001                     high   196   8:45 3:29    allyl       0.001                     low    331   18:20                                       3:37    2-hydroxyethyl                0.001                     low    247   4:48 3:35    2-hydroxyethyl                0.010                     low    249   4:30 3:20    dicyclopentyl                0.001                     very high                            199   3:40 4:11    isobornyl   0.000                     incompatible    isophoronyl 0.010                     incompatible    Dimethacrylates    1,6-hexanediol                0.001                     high   241   7:54 3:34    ethylene glycol (EG)                0.001                     low    275   2:48 3:37    ethylene glycol                0.005                     low    274   2:52 3:50    diethylene glycol                0.001                     medium >210  4:03 2:12    diethylene glycol                0.010                     medium 252   5:40 3:13    triethylene glycol                0.001                     medium 241   3:18 3:17    tetraethylene glycol                0.001                     medium 229   2:52 3:46    neopentyl glycol                0.001                     high   235   4:20 4:09    ethoxylated BPA                0.001                     very high                            171   8:50 7:30    C14 diol    0.001                     incompatible    Trimethacrylate    trimethylol propane                0.001                     high   228   2:28 4:25    Mixtures    30 EG dimethacrylate/                0.010                     medium 295   1:49 3:12    10 N-vinyl pyrrolidinone    30 EG dimethacrylate/                0.010                     medium 286   3:11 3:29    10 divinyl benzene    30 vinyl toluene/                0.200                     low    289   16:10                                       4:44    10 N-vinyl pyrrolidinone    __________________________________________________________________________     *This was considered unsatisfactory, but when ethoxylated BPA     dimethacrylate was included to make a 3part mixture, viscosity was     lowered. Of all the above substitutions for monomer, only the Nvinyl     pyrrolidinone, divinyl benzene, ethylene glycol dimethacrylate, cyclohexy     methacrylate, and vinyl toluene were not ruled out. The rest were     eliminated from consideration because they were slow to react with     polyester as shown by long gel time and/or low exotherm or they were not     sufficient ly compatible with polyester as shown by high viscosity or the     outright failure to dissolve.     .sup.1) Mod L is 25% hydroquinone in propylene glycol.

Liquid resin properties measured in the experiments reported below weregel time, (reported in the tables herein in minutes and seconds, as13:17, for example), room temperature interval time, which is the timebetween gelation and the exothermic peak, room temperature exothermicpeak which is the highest temperature reached in a 100 g mass of resinduring the curing process, Brookfield viscosity, and Barcol hardness byASTM D2583. For volatile emissions, we followed the Rule 1162 StandardMethod for Static Volatile Emissions of the South Coast Air QualityManagement District (California) which is incorporated herein byreference. This test is accepted as a predictor of volatile emissions inthe workplace during spray-up lamination procedures. Its results arereported in two ways--grams per square meter of weight loss, and thetime of emissions, in minutes and seconds. The latter measuremententails noting the point in time in which weight loss is no longerrecorded, thus requiring that weight be monitored beyond the time noted.The test requirements are as follows: An environment at 77° C. and 50%relative humidity is maintained. If a controlled environment is notavailable, conditions should be reported for which measurements aremade. A 200 gm pre-promoted resin is weighed out into a suitable dry andclean container. The container is covered and placed in a 25° C.temperature bath. A balance is placed in a draft free enclosure. Agallon lid is cleaned with solvent and wiped dry. The diameter ismeasured to the nearest 0.1 cm. The gallon lid is placed on an invertedpaper or plastic cup mounted on the balance pan. A bent paper clip ispositioned in the center of the gallon lid. This weight (TARE WEIGHT) isrecorded. The container is taken from the temperature bath and anappropriate volumetric or weight measure of catalyst is added. A timeris started at this point. The catalyst is mixed with the resin for oneminute. The INITIAL WEIGHT is determined by pouring 100.0±0.5 gm ofcatalyzed resin into the can lid and recording the weight. Next, thepaper clip is used to determine when the resin has hardened sufficientlyto allow the resin or lid to be lifted. The time (gel time) is recordedat this point. The resin is then allowed to harden in the can lid andevery 15 minutes it is reweighed until concurrent weights agree towithin 0.05 gm. This is recorded as the FINAL WEIGHT. The entireprocedure should be repeated until duplicate samples agree to thenearest 5 gm/m².

The volatile emissions per square meter are calculated as follows:##EQU1##

The clear castings tests adopted were as follows:

1. Tensile strength--ASTM D638.

2. Tensile modulus--ASTM D638.

3. Elongation--ASTM D638.

4. Flexural strength--ASTM D790.

5. Flexural modulus--ASTM D790.

6. Heat deflection temperature--ASTM D648.

7. Water absorption at 150° F.--ASTM D570 (modified).

The water absorption test was modified as follows: the temperature wasset at 150° F. and long term immersion was set at one week. In the datareported in Table I, Resin A is as described above in terms of weight;it is, in molar equivalents, a polyester resin composed of 1.0 molemaleic anhydride, 2.0 moles phthalic anhydride, 0.42 mole diethyleneglycol and 2.71 moles propylene glycol. Resin B is similar to Resin Awith a lower viscosity by an adjustment of the cook, as is known in theart. Sartomer CD480 is ethoxylated bisphenol-A dimethacrylate where mand n in the above formula total 10. Sartomer 348 is ethoxylatedbisphenol-A dimethacrylate where m and n in the above formula areboth 1. Mod L is 25% hydroquinone and 75% propylene glycol.

From the data in Table I, it can be seen that formulation Z has betterthan acceptable resin properties and clear casting properties, and hasvolatile emissions of about one-fifth the rate of the more or lessclassical commercial resin A2.

In Tables II and III, nine additional formulations are shown. From theseit will be seen that cyclohexyl methacrylate causes undesirableproperties when used as the only material in addition to the base resinand the ethoxylated BPA dimethacrylate. But there are extraordinarilylow emissions from all nine of the formulations. The use of vinyltoluene to reduce the viscosity is certainly not detrimental toemissions results.

                                      TABLE I    __________________________________________________________________________                      A2    C2    S     Z     A1    O    __________________________________________________________________________    RESIN    Resin A           60.00 60.00 40.00 35.00 35.00 --    Resin B           --    --    --    --    --    45.00    Sartomer CD480    --    --    15.00 15.00 15.00 10.00    Sartomer 348      --    --    20.00 20.00 20.00 15.00    EG Dimethacrylate --    --    25.00 10.00 20.00 30.00    Vinyl Toluene     --    40.00 --    10.00 --    --    Cyclohexyl Methacrylate                      --    --    --    10.00 --    Divinyl Benzene   --    --    --    --    10.00 --    Styrene           40.00 --    --    --    --    --    Mod L             0.20  0.22  0.06  0.12  0.12  0.06    RESIN PROPERTIES    Gel time, min:sec 12:59 13:17 21:18 18:29 11:30 5:20    Interval, min:sec  5:58  6:54  4:32  4:11  3:26 3:19    Exotherm peak, °F.                      345   324   249   276    294  245    Viscosity, cps, 75° F.                      315   340   1,390 426   624   396    1162 Emissions, G/M2                      31.5  20.6E 3.6   6.1   9.7   3.6    Barcol hardness    45 minutes        45    42    47    44    52    34    One hour          45    43    50    48    53    36    24 hours          49    49    52    51    54    36    CLEAR CASTING PROPERTIES    Tensile strength, psi                      9,308 7,555 8,069 9,635 8,176 10,179    Ten. modulus, 10-5 psi                      0.549 0.534 0.466 0.565 0.575 0.567    Elongation, %     1.9   1.6   3.2   2.7   1.9   2.3    Flexural strength, psi                      16,008                            15,317                                  10,475                                        16,889                                              15,780                                                    16,013    Flex modulus, 10-5 psi                      0.586 0.573 0.322 0.444 0.482 0.498    Heat deflect. temp, °F.                      144   138   169   142   147   141    Water absorption, % at 150° F.    One day           0.89  0.91  1.01  1.19  1.26  1.43    7 days            1.89  1.89  2.12  1.65  1.76  2.14A    __________________________________________________________________________     E -- This value was estimated based on the difference in results caused b     using different end points for the 1162 test.     A -- The surfaces of the test specimens were alligatored. This indicates     more severe problem than the weight gain indicates.

                                      TABLE II    __________________________________________________________________________    Low VOC Laminating Resins Based on General Purpose Polyester Polymer    Resin         E-3B F-3   G-3  H-3  I-3    __________________________________________________________________________    Composition    Resin A       35.00                       35.00 35.00                                  35.00                                       35.00    Sartomer 480  15.00                       15.00 15.00                                  15.00                                       15.00    Sartomer 348  20.00                       20.00 20.00                                  20.00                                       20.00    EG Dimethacrylate                  --   15.00 --   15.00                                       20.00    Cyclohexyl Methacrylate                  30.00                       15.00 15.00                                  --   05.00    Vinyl Toluene --   --    15.00                                  15.00                                       05.00    Mod L         00.00                       00.00 00.17                                  00.17                                       00.06    12% Cobalt    00.30                       00.30 00.30                                  00.30                                       00.30    16% Potassium 00.20                       00.20 00.20                                  00.20                                       00.20    Dimethyl Acetoacetamide                  00.30                       00.30 00.30                                  00.30                                       00.30    Resin Properties    Gel Time, min:sec                  48:00                       27:55 33:52                                  25:10                                       30:40    Interval, min:sec                  10:49                       05:01 07:07                                  03:51                                       05:23    Exotherm, °F.                  229  239   244  291  258    Viscosity, cps @ 75° F.                  1,280                       1,085 560  650  930    Barcol    45 minutes    00.0 31.7  00.0 00.0 26.6    one hour      00.0 47.3  29.7 47.0 48.7    two hours     00.0 48.6  45.6 50.8 51.0    three hours   00.0 48.2  45.9 49.8 51.1    four hours    00.0 48.6  46.0 50.3 51.2    24 hours      38.2 48.4  47.2 50.7 51.5    1162 Emissions, G/M2                  2.4  6.1   3.6  4.2  3.0    Emissions, min:sec                  60:55                       36:42 53:46                                  29:15                                       36:18    Properties of a Clear Casting    HDT, °F.                  129  138   138  159  163    Tensile Strength, psi                  9,290                       8,980 9,580                                  9,140                                       6,050    Ten Modulus, 10-5 psi                  0.451                       0.481 0.485                                  0.544                                       0.587    Elongation, % 3.10 2.40  2.50 2.00 1.20    Flexural Strength, psi                  14,400                       >16,130                             18,400                                  19,660                                       17,150    Flex modulus, 10-5 psi                  0.488                       0.520 0.662                                  0.664                                       0.633    Water Absorption @ 150° F.    24 hours      1.06 1.08  1.07 0.95 1.07    seven days    2.43 2.19  1.78 1.84 2.06    __________________________________________________________________________

                                      TABLE III    __________________________________________________________________________    Low VOC Laminating Resins Based on General Purpose Polyester Polymer    Resin         U-3   ZA    V-3    Z    __________________________________________________________________________    Composition    Resin A       35.00 35.00 35.00  35.00    Sartomer 480  15.00 15.00 15.00  15.00    Sartomer 348  20.00 20.00 20.00  20.00    EG Dimethacrylate                  15.00 10.00 --     10.00    Cyclohexyl Methacrylate                  05.00 10.00 --     10.00    Vinyl Toluene 10.00 10.00 30.00  10.00    Mod L         00.13 00.06 00.20  00.12    12% Cobalt    00.30 00.30 00.30  00.30    16% Potassium 00.20 00.20 00.20  00.20    Dimethyl Acetoacetamide                  00.30 00.30 00.30  00.30    Resin Properties    Gel Time, min:sec                  38:05 38:15 37:36  18:29    Interval, min:sec                  06:07 07:37 09:49  04:11    Exotherm, °F.                  277   277   273    276    Viscosity, cps @ 75° F.                  790   710   382    426    Barcol    45 minutes    00.0  00.0  00.0   44.0    one hour      37.0  32.2  39.9   48.0    two hours     48.6  47.2  46.0   --    three hours   48.5  47.6  46.2   --    four hours    48.5  47.8  46.9   --    24 hours      48.5  48.7  46.9   51.0    1162 Emissions, G/M2                  7.3   2.4   1.8    6.1    Emissions, min:sec                  44:22 48:20  51:35 --    Properties of a Clear Casting    HDT, °F.                  136   138   138    142    Tensile Strength, psi                  10,120                        10,370                              9,500  9,635    Ten Modulus, 10-5 psi                  0.489 0.540 0.501  0.565    Elongation, % 2.70  2.60  2.30   2.70    Flexural Strength, psi                  18,750                        19,410                              >19,150                                     16,889    Flex Modulus, 10-5 psi                  --    --    --     0.444    Water Absorption @ 150° F.    24 hours      1.06  1.04  0.81   1.19    seven days    1.78  1.87  1.43   1.65    __________________________________________________________________________

Based on experimental work performed subsequent to the filing of theparent application Ser. No. 024,022, now abandoned, vinyl toluene isuseful in our composition and method. Accordingly, our inventioncomprises a composition comprising (a) the base polyester polymer(resin) as described above and the alkoxylated bisphenol-A diacrylate ordimethacrylate in a ratio of 2:1 to 0.5:1 and (b) about 20% to about60%, based on the total of (a) and (b), of vinyl toluene. In Tables I,II, and III, the various "Sartomer" compositions, i.e. the ethoxylatedbisphenol-A dimethacrylates, have 1 and 5 ethoxy groups on each side ofthe bisphenol-A; however, we may employ a single compound or compoundshaving any variation of combinations of ethoxy or propoxy groups fromtwo to about 20 groups, preferably a total of 2 to 8 alkoxy groups.

We claim:
 1. Method of laminating a solid formed body comprising (a)providing a forming surface having a desired positive or negative shape,(b) providing a liquid mixture comprising (1) about two parts by weightunsaturated polyester resin, (2) about one part to about four parts byweight alkoxylated bisphenol-A diacrylate or dimethacrylate, (3) about20% to about 60%, based on the total weight of (1) and (2), of a monomerof the formula ##STR3## where one H connected to the ring is substitutedby CH₃, and (4) an effective amount of a polymerization catalyst, (c)applying said mixture to said forming surface at ambient temperatures inlayers while permitting said layers incrementally to polymerize, therebybuilding said shaped article, and wherein no more than 20.0 g/m² ofvolatile emissions as measured by Section 1162 of the Regulations of theSouth Coast (California) Air Quality District are created, and (d)removing the finished solid formed body from said surface.
 2. Method ofclaim 1 wherein the alkoxylated BPA is a dimethacrylate and has about 2to about 20 alkoxy groups.
 3. Method of claim 1 wherein said mixture isapplied by spraying.
 4. Method of claim 1 wherein said mixture includesglass fibers.
 5. Method of claim 2 wherein said alkoxy groups are ethoxygroups.
 6. Method of claim 1 wherein said alkoxylated BPA dimethacrylatehas from 2 to 8 alkoxy groups.